Getting ComboBox Strings to Appear with an ATL Project

Place in your dialogbox code:

LRESULT CMyDialog::OnInitDialog(UINT uMsg, WPARAM
wParam, LPARAM lParam, BOOL& bHandled)
{
 ExecuteDlgInit( m_hWnd, MAKEINTRESOURCE(IDD) );
 return 1;
}

#include "stdafx.h"
#include 
#include 
#include "DoDlgInit.h"

BOOL ExecuteDlgInit(HWND hwndDlg, LPVOID lpResource);

BOOL ExecuteDlgInit(HWND hwndDlg, LPCTSTR lpszResourceName)
{
 // find resource handle
 LPVOID lpResource = NULL;
 HGLOBAL hResource = NULL;
 if (lpszResourceName != NULL)
 {
  HRSRC hDlgInit =
   ::FindResource(_Module.m_hInstResource,
                  lpszResourceName, _ATL_RT_DLGINIT);
  if (hDlgInit != NULL)
  {
   // load it
   hResource = LoadResource(_Module.m_hInstResource, hDlgInit);
   if (hResource == NULL)
    return FALSE;
 
   // lock it
   lpResource = LockResource(hResource);
   _ASSERT(lpResource != NULL);
  }
 }

 // execute it
 BOOL bResult = ExecuteDlgInit(hwndDlg, lpResource);

 // cleanup
 if (lpResource != NULL && hResource != NULL)
 {
  UnlockResource(hResource);
  FreeResource(hResource);
 }
 
 return bResult;
}

BOOL ExecuteDlgInit(HWND hwndDlg, LPVOID lpResource)
{
 BOOL bSuccess = TRUE;
 if (lpResource != NULL)
 {
  UNALIGNED WORD* lpnRes = (WORD*)lpResource;
  while (bSuccess && *lpnRes != 0)
  {
   WORD nIDC = *lpnRes++;
   WORD nMsg = *lpnRes++;
   DWORD dwLen = *((UNALIGNED DWORD*&)lpnRes)++;

   // In Win32 the WM_ messages have changed.  They have
   // to be translated from the 32-bit values to 16-bit
   // values here.

   #define WIN16_LB_ADDSTRING  0x0401
   #define WIN16_CB_ADDSTRING  0x0403
   #define AFX_CB_ADDSTRING    0x1234

   // unfortunately, WIN16_CB_ADDSTRING == CBEM_INSERTITEM
   if (nMsg == AFX_CB_ADDSTRING)
    nMsg = CBEM_INSERTITEM;
   else if (nMsg == WIN16_LB_ADDSTRING)
    nMsg = LB_ADDSTRING;
   else if (nMsg == WIN16_CB_ADDSTRING)
    nMsg = CB_ADDSTRING;

#ifdef _DEBUG
   // For AddStrings, the count must exactly delimit the
   // string, including the NULL termination.  This check
   // will not catch all mal-formed ADDSTRINGs, but will
   // catch some.
   if (nMsg == LB_ADDSTRING 
   || nMsg == CB_ADDSTRING 
   || nMsg == CBEM_INSERTITEM)
    _ASSERT(*((LPBYTE)lpnRes + (UINT)dwLen - 1) == 0);
#endif

   if (nMsg == CBEM_INSERTITEM)
   {
    USES_CONVERSION;
    COMBOBOXEXITEM item;
    item.mask = CBEIF_TEXT;
    item.iItem = -1;
    item.pszText = A2T(LPSTR(lpnRes));

    if (::SendDlgItemMessage(hwndDlg, nIDC, nMsg, 0, (LPARAM) &item) 
        == -1)
     bSuccess = FALSE;
   }
   else if (nMsg == LB_ADDSTRING || nMsg == CB_ADDSTRING)
   {
    // List/Combobox returns -1 for error
    if (::SendDlgItemMessageA(hwndDlg, nIDC, nMsg, 0, (LPARAM) lpnRes) 
        == -1)
     bSuccess = FALSE;
   }

   // skip past data
   lpnRes = (WORD*)((LPBYTE)lpnRes + (UINT)dwLen);
  }
 }
 
 // send update message to all controls after all other siblings loaded
 // if (bSuccess)
 // SendMessageToDescendants(WM_INITIALUPDATE, 0, 0, FALSE, FALSE);

 return bSuccess;
}